CSX no longer uses the Cumberland hump along with most hump yards across their system (including the one near me), so that is why the services do flat switching. Although it would be nice if we could use the scenario editor to create our own switching scenarios that we could use the hump.
None of the infrastructure is present to use it as a hump yard. It would also require a hump yard system added to the game. So basically it’s never going to happen.
There's no mention of the TSW2's time frame and I have no idea when CSX stopped using the hump yard. Surely someone can enlighten me?
https://trn.trains.com/news/news-wire/2017/05/23-selkirk-hump Article from 2017 (CSX's Buffalo, NY hump yard is not shown on the map. It converted to flat switching a few years ago)